At present, the power ON/OFF function of a circuit breaker is realized by opening/closing a handle of the circuit breaker. In the process of using a circuit breaker, in order to avoid the case that the safety of an operator is under threat in power-on and power-off situations or during maintenance because of an unintended mistaken operation, causing unpredictable consequences, it is particularly important to maintain the position of the handle of the circuit breaker, so that the handle will not be operated mistakenly.